Baltic Flint constitutes a flintsourcerers nightmare. It is something like having your place invaded by a horde of barbarians who smash up the cabinet with your reference collection, rip open the bags, empty the boxes and scatter the contents all over the floor. Then they start stamping on the stones, crushing most of the larger specimens. And after you have cleaned up the mess a bit, they come back and do it again.
The above analogy might sound a bit drastic, but it is basically what happened on a geological scale during the glacial cycles of the Pleistocene. The enormous glaciers pushing south from the Fenno-Scandian Shield ground up the soft Upper Cretaceous and Lower Paleocene chalks of Southern Scandinavia and Northern Germany, picking up the resistant flint nodules, and scattering them as far south as Central Germany, Northern Moravia an Silesia, making the whole of Northern and Northwestern continental Europe one great big, undifferentiated flint source.
Very inaccurate representation of the "flint-line" in Germany and the Netherlands
As most of the coarser glacial deposits like boulder clay/till and fluvo-glacial gravel contain flint, the southernmost occurrence of "Baltic" material coincides more or less with the maximum extend of the glacial cover. This boundary is in the German literature therefore aptly know as the "Feuersteinlinie" or flint-line. In the picture above we have sketched this line for Germany and the Netherlands (adapted from Zimmermann 1995) to give an idea of where erratic flints can be found. As all rivers in the area drain towards the North Sea and Baltic Sea, no further natural transport towards the south has taken place, confining the 'problem' to the Northern European Plain.
Because the different Ice Ages, predominantly Elster and Saale (yes we know, we should be dividing that one in two glacials, the Drenthe and Warthe, but most literature still lumps them together), reached their respective southernmost limits in different areas, the 'flintline' doesn't represent one chronological horizon. In the Netherlands for example, the maximum glacial cover occurred within the Saale glaciation, whereas the furthest advance on the German/Czech border dates to the Elster 1 glacial maximum.
|Similarities and differences:||
As the ice-flows during the separate glacials and, to a lesser extend, stadials were different, there should theoretically be some variation in the types of flint their respective sediments contain, but very little work has been done on this aspect. We get the impression that, at least in Germany, the more recent glacial deposits (dating to the Weichsel glacial) contain a higher amount of opaque grey flint, but as those sediments always contain reworked older material, this can only be a matter of proportion, and not an absolute. We hope we can say something more on the subject when our database comprises more well-dated samples from diverse settings and areas.
In the meantime, we present here some samples from the region where the FlintSource project started, Saxony in Eastern Germany
There are four main types of flint to be found within erratic material:
The very high variability and hardly-studied petrography of erratic flints makes sourcing of lithics in glacially covered areas very difficult indeed. There is one rule of thumb you should adhere to at all times: if you can't prove it isn't erratic flint, you should assume it is a regional material from glacial deposits, even if you haven't found the material locally yet. This of course limits the possibilities of flint-typing in large tracts of Northern Europe quite unpleasantly, but there are some bright spots as all Baltic Flint dates to the Upper Cretaceous and Lower Paleocene. So if you can prove the material is Jurassic in age (like Abensberg-Arnhofen, Chocolate Flint, Banded Flint and Baiersdorf, to name a few materials that are regularly found North of the flintline in archaeological contexts), you can be sure you have an imported piece in your hands.
There are of course Cretaceous flints that either occur within the glacially covered areas (like Red Helgoland Flint) or are imported into it (e.g. Grand Pressigny, Valkenburg, and to a lesser extend Rijckholt), that can be distinguished from Baltic materials. Especially with the last one, care has to be taken as there are some (rare) varieties of Erratics that can look macroscopically very similar to the Lanaye-Lixhe flint, as Rijckholt should be called more correctly.
At this point we have to contradict two popular misunderstandings. The first one is that erratic flint can always be recognized by its worn down cortex, the other one is that it is inherently of inferior quality. Even with the washed-out and glacio-fluvially transported material from the sand- and gravel pits in Dresden-Klotzsche and Serbitz there are specimens with (patches of) chalky cortex still intact. With some nodules from the boulder-clay, where they sometimes are even still embedded in blocks of chalk like in Gedser Odde, there is no way to tell if they were freshly extracted from the chalk or are erratic. On the other hand, if the surface is completely worn and pitted with a strong polish, sometimes even tending towards a metallic sheen, you can be quite confident it was glacially transported.
As for the inferior quality: it is true that quite a lot of the flint found in glacial deposits is internally cracked, either due to mechanical stress or caused by frost-weathering, it certainly can be of very high quality. Again, fluvially transported material is often stronger weathered, but nodules from till can be as fresh and intact as freshly mined flint.
|Extractability and prehistoric use:||
As it is ubiquitous and often easily gathered from the surface, Baltic Flint has been used extensively during all of prehistory in Northern and Northwest Europe, where assemblages often, or even mostly, consist entirely of this type of flint. Imported pieces can be found, to name just a few regions, in Southern Germany (Wischenbarth 1993), Bohemia (e.g. Popelka 1992) and Moravia (Śebela 1997). But care has to be taken with identification, because of the occurrence of similar materials in the Upper Cretaceous of the Southern Netherlands, parts of Belgium, and several locations in Western Germany (for an overview of these sources, see Zimmermann 1995, p. 48)
Most material will have been gathered from the surface, but as a higher percentage of this material will be of inferior quality due to frost-shattering, at least some of it has been dug out of deeper sediments. There are even a few regular open cast mines for baltic flint known, where it has been extracted by means of large pits. The most famous examples of this type of mining are Den of Boddam in Scotland (Saville 1997), Rybniki in Poland (Borkowski et al. 1995), and Bottmersdorf in Germany (Wechler 1991).
|Last modified on:
December 16, 2007
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